Guitar foot controller uses DSP for audio effects

This a screenshot taken from [Pierre’s] demonstration of an electric guitar effects pedal combined with DSP and Pure Data. He pulls this off by connecting the guitar directly to the computer, then feeds the computer’s audio output to the guitar amp.

The foot controls include a pedal and eight buttons, all monitored by an Arduino. Pure Data, a visual programming language, interprets the input coming from the Arduino over USB and alters the incoming audio using digital signal processing. [Pierre] manages the audio connection using the JACK Audio Connection Kit software package.

In the video after the break he’s using a laptop for most of the work, but he has also managed to pull this off with a Raspberry Pi. There’s no audio input on the RPi board, but he’s been using a USB sound card anyway. The other USB port connects the Arduino and he’s in business.

Hi Pierre, so in this demonstration the arduino is monitoring your pedals and sending that info to a computer running PureData which then manipulates the audio from the guitar which is connected to the computer directly rather than going through the pedal? If I got that right then I see two subsystems. One is the arduino based pedal controller, the other is the audio manipulation software.

Quite a few years ago Line6 came up with their tonecore developers kit which is basically a programmable effect pedal with a Freescale Symphony audio DSP. Software-wise it probably lacks the platform portability that you have here but my reason for mentioning it is to ask if a programmable pedal is an end goal for you here?

Personally I like seeing the physical part of the project, no matter how simple the builders think them to be. Without the cabinet, associated controls, there is no way to use the single board computers electronics, and software. In the event there are photos are wiring schematics etc. shown I’m not finding them, not even a clear photo of the project

I’m working on a similar project at the moment. Targetting the OpenPandora and Raspberry. Especially since Miller Puckette himself is now playing around with the Raspberry Pi the Puredata-port should only get better and better :)

I’d like to see some of his Pd-patches and which audio-effects he managed to recreate.